1. Field of the Invention
The present invention relates to an endoscope that allows an operation to rotate an insertion portion relative to an operation portion.
2. Description of the Related Art
Endoscopes each include an elongated flexible insertion portion. The endoscopes are used in, e.g., medical and industrial fields. The insertion portion includes a distal end portion, a bending portion and a flexible tube portion having flexibility in this order from the distal end side. At a proximal end portion of the insertion portion, an operation portion, which is held and operated by an operator, is disposed.
The elongated insertion portion may be inserted to a lumen including a plurality of branch portions such as a bronchus. In this case, a surgeon repeatedly performs, e.g., an operation to bend the bending portion and an operation to twist the operation portion and the insertion portion to insert the insertion portion to a deep part of the lumen.
Japanese Patent Application Laid-Open Publication No. 2010-234058 discloses an endoscope that allows an operation to rotate an insertion portion relative to an insertion portion. With the endoscope, for example, when a surgeon performs an operation to rotate the insertion portion relative to the operation portion, the amount of strength required for the rotation increases as a rotational position of the insertion portion moves away from a neutral position.
Accordingly, the surgeon can grasp the rotational position relative to the neutral position, from the change in the amount of strength.
In the case of the endoscope disclosed in Japanese Patent Application Laid-Open Publication No. 2010-234058, when the insertion portion is inserted to a bronchus, a surgeon performs an operation to rotate the insertion portion relative to the operation portion instead of performing a twisting operation to twist the operation portion and the insertion portion, while observing an endoscopic image displayed on a screen of a monitor.
Then, when the surgeon inserts a distal end portion of the insertion portion to, for example, a main bronchus, confirms on the endoscopic image that the insertion portion has rotated by 90 degrees, and then makes the bending portion bend, for example, upward to insert the distal end portion of the insertion portion to the main bronchus. Subsequently, the surgeon repeatedly performs an operation to properly rotate the insertion portion relative to the operation portion and an operation to properly bend the bending portion to insert the distal end portion of the insertion portion to a target site.
With this configuration, making the insertion portion rotate relative to the operation portion instead of the twisting operation enhances the operability and reduces a period of time required for the procedure, resulting in substantial reduction in burden on a surgeon and a patient.